Optical system, optical apparatus and method for manufacturing the optical system, and zoom optical system, optical apparatus and method for manufacturing the zoom optical system

ABSTRACT

This optical system (LS) has an aperture diaphragm (S) and a negative lens (L4) disposed closer to an object side than the aperture diaphragm (S) and satisfies the following conditional expression.−0.010&lt;ndN1−(2.015−0.0068×νdN1),50.00&lt;νdN1&lt;65.00, 0.545&lt;θgFN1,−0.010&lt;θgFN1−(0.6418−0.00168×νdN1).Where, ndN1 is a refractive index of the negative lens with respect to a d-line,vdN1 is an Abbe number of the negative lens based on the d-line, andθgFN1 is a partial dispersion ratio of the negative lens.

TECHNICAL FIELD

The present invention relates to an optical system, an optical apparatus and a method for manufacturing the optical system, and a zoom optical system, an optical apparatus, and a method for manufacturing the zoom optical system.

TECHNICAL BACKGROUND

In recent years, the image resolutions of imaging elements included in imaging apparatuses, such as digital cameras and video cameras, have been improved. It is desired that a photographing lens provided in an imaging apparatus including such an imaging element be a lens of which not only the reference aberrations (aberrations for single-wavelength aberrations), such as the spherical aberration and the coma aberration, be favorably corrected, but also chromatic aberrations be favorably corrected so as not to cause color bleeding for a white light source, and which have a high resolution. In particular, for correction of the chromatic aberrations, it is desirable that not only primary achromatism be achieved but also secondary spectrum be favorably corrected. As means for correcting the chromatic aberrations, for example, a method of using a resin material having anomalous dispersion characteristics (for example, see Patent literature 1) has been known. As described above, accompanied by the recent improvement in imaging element resolution, a photographing lens with various aberrations being favorably corrected has been desired.

PRIOR ARTS LIST Patent Document

Patent literature 1: Japanese Laid-Open Patent Publication No. 2016-194609(A)

SUMMARY OF THE INVENTION

The optical system according to the present invention comprises: an aperture stop; and a negative lens that is disposed closer to an object than the aperture stop. The negative lens satisfies the following conditional expressions,

−0.010<ndN1−(2.015−0.0068×νdN1),

50.00<νdN1<65.00,

0.545<θgFN1,

−0.010<θgFN1−(0.6418−0.00168×νdN1),

where ndN1: a refractive index of the negative lens for d-line,

νdN1: an Abbe number of the negative lens with reference to d-line, and

θgFN1: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN1, a refractive index of the negative lens for F-line is nFN1, and a refractive index of the negative lens for C-line is nCN1:

θgFN1=(ngN1−nFN1)/(nFN1−nCN1).

The optical apparatus according to the present invention comprises the optical system described above.

A method for manufacturing an optical system according to the present invention comprises a step of arranging each lens in a lens barrel so that the optical system comprises: an aperture stop; and a negative lens that is disposed closer to an object than the aperture stop, the negative lens satisfying the following conditional expressions,

−0.010<ndN1−(2.015−0.0068×νdN1),

50.00<νdN1<65.00,

0.545<θgFN1,

−0.010<θgFN1−(0.6418−0.00168×νdN1),

where ndN1: a refractive index of the negative lens for d-line,

νdN1: an Abbe number of the negative lens with reference to d-line, and

θgFN1: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN1, a refractive index of the negative lens for F-line is nFN1, and a refractive index of the negative lens for C-line is nCN1:

θgFN1=(ngN1−nFN1)/(nFN1−nCN1).

A zoom optical system according to the present invention comprises: a plurality of lens groups that include lens groups having negative refractive powers, wherein upon zooming, a distance between the lens groups adjacent to each other changes, and an object-side negative lens group disposed closest to an object among the lens groups having the negative refractive powers includes a negative lens that satisfies the following conditional expressions,

−0.010<ndN3−(2.015−0.0068×νdN3),

50.00<νdN3<65.00,

0.545<θgFN3,

−0.010<θgFN3−(0.6418−0.00168×νdN3),

where ndN3: a refractive index of the negative lens for d-line,

νdN3: an Abbe number of the negative lens with reference to d-line, and

θgFN3: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN3, a refractive index of the negative lens for F-line is nFN3, and a refractive index of the negative lens for C-line is nCN3:

θgFN3=(ngN3−nFN3)/(nFN3−nCN3).

The optical apparatus according to the present invention comprises the zoom optical system described above.

A method for manufacturing a zoom optical system that includes a plurality of lens groups including lens groups having negative refractive powers according to the present invention. The method comprises a step of arranging each lens in a lens barrel so that upon zooming, a distance between the lens groups adjacent to each other changes, and an object-side negative lens group disposed closest to an object among the lens groups having the negative refractive powers includes a negative lens that satisfies the following conditional expressions,

−0.010<ndN3−(2.015−0.0068×νdN3),

50.00<νdN3<65.00,

0.545<θgFN3,

−0.010<θgFN3−(0.6418−0.00168×νdN3),

where ndN3: a refractive index of the negative lens for d-line,

νdN3: an Abbe number of the negative lens with reference to d-line, and

θgFN3: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN3, a refractive index of the negative lens for F-line is nFN3, and a refractive index of the negative lens for C-line is nCN3:

θgFN3=(ngN3−nFN3)/(nFN3−nCN3).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to First Example;

FIGS. 2A, 2B and 2C are graphs respectively showing various aberrations of the optical system according to First Example upon focusing on infinity, upon focusing on an intermediate distant object and upon focusing on a short distant object;

FIG. 3 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Second Example;

FIGS. 4A, 4B and 4C are graphs respectively showing various aberrations of the optical system according to Second Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 5 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Third Example;

FIGS. 6A, 6B and 6C are graphs respectively showing various aberrations of the optical system according to Third Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 7 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Fourth Example;

FIGS. 8A, 8B and 8C are graphs respectively showing various aberrations of the optical system according to Fourth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 9 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Fifth Example;

FIGS. 10A, 10B and 10C are graphs respectively showing various aberrations of the optical system according to Fifth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 11 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Sixth Example;

FIGS. 12A, 12B and 12C are graphs respectively showing various aberrations of the optical system according to Sixth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 13 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Seventh Example;

FIGS. 14A, 14B and 14C are graphs respectively showing various aberrations of the optical system according to Seventh Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 15 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Eighth Example;

FIGS. 16A, 16B and 16C are graphs respectively showing various aberrations of the optical system according to Eighth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 17 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Ninth Example;

FIGS. 18A, 18B and 18C are graphs respectively showing various aberrations of the optical system according to Ninth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 19 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Tenth Example;

FIGS. 20A, 20B and 20C are graphs respectively showing various aberrations of the optical system according to Tenth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 21 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Eleventh Example;

FIGS. 22A, 22B and 22C are graphs respectively showing various aberrations of the optical system according to Eleventh Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 23 shows a configuration of a camera that includes the optical system according to each embodiment;

FIG. 24 is a flowchart showing a method of manufacturing the optical system according to a first embodiment; and

FIG. 25 is a flowchart showing a method of manufacturing the optical system (zoom optical system) according to a second embodiment.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, preferable embodiments according to the present invention are described. First, a camera (optical apparatus) that includes an optical system according to each embodiment is described with reference to FIG. 23. As shown in FIG. 23, the camera 1 is a digital camera that includes the optical system according to each embodiment, as a photographing lens 2. In the camera 1, light from an object (photographic subject), not shown, is collected by the photographing lens 2, and reaches an imaging element 3. Accordingly, the light from the photographic subject is captured by the imaging element 3, and is recorded as a photographic subject image in a memory, not shown. As described above, a photographer can take the image of the photographic subject through the camera 1. Note that this camera may be a mirrorless camera, or a single-lens reflex camera that includes a quick return mirror.

Next, the optical system according to a first embodiment is described. As shown in FIG. 1, an optical system LS(1) as an example of an optical system (photographing lens) LS according to the first embodiment comprises: an aperture stop S; and a negative lens (L4) that is disposed closer to an object than the aperture stop S, and satisfies following conditional expressions (1) to (4).

−0.010<ndN1−(2.015−0.0068×νdN1),   (1)

50.00<νdN1<65.00,   (2)

0.545<θgFN1,   (3)

−0.010<θgFN1−(0.6418−0.00168×νdN1),   (4)

where ndN1: is a refractive index of the negative lens for d-line,

νdN1: an Abbe number of the negative lens with reference to d-line, and

θgFN1: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN1, a refractive index of the negative lens for F-line is nFN1, and a refractive index of the negative lens for C-line is nCN1:

θgFN1=(ngN1−nFN1)/(nFN1−nCN1).

Note that the Abbe number νdN1 of the negative lens with reference to d-line is defined by the following expression:

νdN1=(ndN1−1)/(nFN1−nCN1).

According to the first embodiment, the optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected, and the optical apparatus that includes this optical system can be achieved. The optical system LS according to the first embodiment may be an optical system LS(2) shown in FIG. 3, an optical system LS(3) shown in FIG. 5, an optical system LS(4) shown in FIG. 7, an optical system LS(5) shown in FIG. 9, or an optical system LS(6) shown in FIG. 11. The optical system LS according to the first embodiment may be an optical system LS(7) shown in FIG. 13, an optical system LS(8) shown in FIG. 15, an optical system LS(9) shown in FIG. 17, an optical system LS(10) shown in FIG. 19, or an optical system LS(11) shown in FIG. 21.

The conditional expression (1) defines an appropriate relationship between the refractive index of the negative lens for d-line and the Abbe number with reference to d-line. By satisfying the conditional expression (1), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration can be favorably performed.

If the corresponding value of the conditional expression (1) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (1) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (1) may be set to −0.001, 0.000, 0.003, 0.005 or 0.007, or further to 0.008.

Note that the upper limit value of the conditional expression (1) may be set to less than 0.150. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (1) to 0.100, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (1) may be set to 0.080, 0.060 or 0.050, or further to 0.045.

The conditional expression (2) defines an appropriate range of the Abbe number of the negative lens with reference to d-line. By satisfying the conditional expression (2), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed.

If the corresponding value of the conditional expression (2) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (2) to 50.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (2) may be set to 51.00, 51.50 or 52.00, or further to 52.40.

By setting the upper limit value of the conditional expression (2) to 64.00, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (2) may be set to 63.00, 62.50, 62.00, 61.50, 61.00 or 60.00, or further to 59.50.

The conditional expression (3) appropriately defines the anomalous dispersion characteristics of the negative lens. By satisfying the conditional expression (3), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (3) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (3) to 0.547, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (3) may be set to 0.548 or 0.549, or further to 0.550.

The conditional expression (4) appropriately defines the anomalous dispersion characteristics of the negative lens. By satisfying the conditional expression (4), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (4) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (4) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (4) may be set to −0.001.

Note that the upper limit value of the conditional expression (4) may be set to less than 0.040. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (4) to 0.030, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (4) may be set to 0.025, or further to 0.020.

Preferably, the optical system LS according to the first embodiment consists of: the aperture stop S; a front group GF disposed closer to the object than the aperture stop S; and a rear group GR disposed closer to an image than the aperture stop S, wherein the front group GF, which includes the negative lens, satisfies the following conditional expression (5),

−10.00<(−fN1)/fF<10.00,   (5)

where fN1: the focal length of the negative lens, and

fF: a focal length of the front group GF; the focal length of the front group GF in the wide angle end state in a case where the optical system LS is a zoom optical system.

The conditional expression (5) defines an appropriate relationship between the focal length of the negative lens and the focal length of the front group GF. By satisfying the conditional expression (5), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (5) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (5) to −9.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (5) may be set to −9.00, −8.50, −8.00, −7.00, −5.00, −3.00, −1.50, −0.05 or 0.05, or further to 0.10.

By setting the upper limit value of the conditional expression (5) to 8.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (5) may be set to 7.50, 6.50, 5.00 or 4.00, or further to 3.00.

In the optical system LS according to the first embodiment, preferably, the negative lens satisfies the following conditional expression (6),

0.10<(−fN1)/f<15.00   (6)

where fN1: the focal length of the negative lens, and

f: a focal length of the optical system; the focal length of the optical system LS in the wide angle end state in a case where the optical system LS is a zoom optical system.

The conditional expression (6) defines an appropriate relationship between the focal length of the negative lens and the focal length of the optical system LS. By satisfying the conditional expression (6), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (6) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (6) to 0.20, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (6) may be set to 0.30, 0.40 or 0.45, or further to 0.50.

By setting the upper limit value of the conditional expression (6) to 14.20, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (6) may be set to 12.00, 10.00 or 8.50, or further to 7.50.

In the optical system LS according to the first embodiment, the negative lens may satisfy the following conditional expression (3-1),

0.555<θgFN1.   (3-1)

The conditional expression (3-1) is an expression similar to the conditional expression (3), and can exert advantageous effects similar to those of the conditional expression (3). By setting the lower limit value of the conditional expression (3-1) to 0.556, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (3-1) to 0.557.

In the optical system LS according to the first embodiment, the negative lens may satisfy the following conditional expression (4-1),

0.010<θgFN1−(0.6418−0.00168×νdN1).   (4-1)

The conditional expression (4-1) is an expression similar to the conditional expression (4), and can exert advantageous effects similar to those of the conditional expression (4). By setting the lower limit value of the conditional expression (4-1) to 0.011, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (4-1) to 0.012.

Note that the upper limit value of the conditional expression (4-1) may be set to less than 0.030. Accordingly, advantageous effects similar to those of the conditional expression (4) can be achieved. In this case, by setting the upper limit value of the conditional expression (4-1) to 0.028, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (4-1) may be set to 0.025 or 0.023, or further to 0.020.

In the optical system LS according to the first embodiment, preferably, the negative lens satisfies the following conditional expression (7),

DN1>0.400 [mm]  (7)

where DN1: a thickness of the negative lens on an optical axis.

The conditional expression (7) appropriately defines the thickness of the negative lens on the optical axis. By satisfying the conditional expression (7), the various aberrations, such as the coma aberration, the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), can be favorably corrected.

If the corresponding value of the conditional expression (7) falls outside of the range, the correction of the various aberrations, such as the coma aberration and the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), becomes difficult. By setting the lower limit value of the conditional expression (7) to 0.450 [mm], the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (7) may be set to 0.490 [mm], 0.550 [mm], 0.580 [mm], 0.650 [mm], 0.680 [mm], 0.750 [mm], 0.800 [mm], 0.850 [mm] , 0.880 [mm], 0.950 [mm], 0.980 [mm], 1.050 [mm], 1.100 [mm], 1.140 [mm], 1.250 [mm], or further to 1.350 [mm].

In the optical system LS according to the first embodiment, preferably, the negative lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the negative lens. Accordingly, even in the case where the negative lens has a lens surface in contact with air (i.e., a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other), it is preferable because variation in optical characteristics due to temperature is small.

In the optical system LS according to the first embodiment, it is desirable that at least one lens surface of an object-side lens surface and an image-side lens surface of the negative lens be in contact with air. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the negative lens. Accordingly, even in a case where a lens surface of the negative lens is in contact with air, it is preferable because the variation in optical characteristics due to temperature is small.

In the optical system LS according to the first embodiment, it is desirable that the negative lens be a glass lens. The secular change of the negative lens that is a glass lens is smaller than that of a resin lens. Accordingly, it is preferable because the variation in optical characteristics due to temperature is small.

Subsequently, referring to FIG. 24, a method for manufacturing the optical system LS according to the first embodiment is schematically described. First, an aperture stop S, and a negative lens closer to an object than the aperture stop S are arranged (step ST1). At this time, each lens is arranged in a lens barrel so that at least one of the negative lenses arranged closer to the object than the aperture stop S satisfies the conditional expressions (1) to (4) and the like (step ST2). According to such a manufacturing method, the optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected can be manufactured.

Next, the optical system according to a second embodiment is described. As shown in FIG. 3, the optical system LS(2) as an example of the optical system (photographing lens) LS according to the second embodiment includes a plurality of lens groups that include lens groups having negative refractive powers. Upon zooming, the distance between the lens groups adjacent to each other changes. An object-side negative lens group (a first lens group G1) disposed closest to an object among the lens groups having the negative refractive powers includes a negative lens (L13) that satisfies the following conditional expressions (11) to (14).

−0.010<ndN3−(2.015−0.0068×νdN3),   (11)

50.00<νdN3<65.00,   (12)

0.545<θgFN3,   (13)

−0.010<θgFN3−(0.6418−0.00168×νdN3),   (14)

where ndN3: a refractive index of the negative lens for d-line,

νdN3: an Abbe number of the negative lens with reference to d-line, and

θgFN3: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN3, a refractive index of the negative lens for F-line is nFN3, and a refractive index of the negative lens for C-line is nCN3:

θgFN3=(ngN3−nFN3)/(nFN3−nCN3).

Note that the Abbe number νdN3 of the negative lens with reference to d-line is defined by the following expression:

νdN3=(ndN3−1)/(nFN3−nCN3).

The optical system LS according to the second embodiment is a zoom optical system that performs zooming by changing the distance between lens groups adjacent to each other. According to the second embodiment, the zoom optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected, and the optical apparatus that includes this zoom optical system can be achieved. The optical system LS (zoom optical system) according to the second embodiment may be an optical system LS(3) shown in FIG. 5, an optical system LS(4) shown in FIG. 7, an optical system LS(5) shown in FIG. 9, or an optical system LS(6) shown in FIG. 11. The optical system LS (zoom optical system) according to the second embodiment may be an optical system LS(7) shown in FIG. 13, an optical system LS(8) shown in FIG. 15, an optical system LS(9) shown in FIG. 17, an optical system LS(10) shown in FIG. 19, or an optical system LS(11) shown in FIG. 21.

The conditional expression (11) defines an appropriate relationship between the refractive index of the negative lens for d-line and the Abbe number with reference to d-line. By satisfying the conditional expression (11), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed.

If the corresponding value of the conditional expression (11) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (11) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (11) may be set to −0.001, 0.000, 0.003, 0.005 or 0.007, or further to 0.008.

Note that the upper limit value of the conditional expression (11) may be set to less than 0.150. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (11) to 0.100, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (11) maybe set to 0.080, 0.060 or 0.050, or further to 0.045.

The conditional expression (12) defines an appropriate range of the Abbe number of the negative lens with reference to d-line. By satisfying the conditional expression (12), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed.

If the corresponding value of the conditional expression (12) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (12) to 50.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (12) maybe set to 51.00, 51.50 or 52.00, or further to 52.40.

By setting the upper limit value of the conditional expression (12) to 64.00, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (12) may be set to 63.00, 62.50, 62.00, 61.50, 61.00 or 60.00, or further to 59.50.

The conditional expression (13) appropriately defines the anomalous dispersion characteristics of the negative lens. By satisfying the conditional expression (13), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (13) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (13) to 0.547, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (13) may be set to 0.548 or 0.549, or further to 0.550.

The conditional expression (14) appropriately defines the anomalous dispersion characteristics of the negative lens. By satisfying the conditional expression (14), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (14) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (14) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (14) may be set to −0.001.

Note that the upper limit value of the conditional expression (14) may be set to less than 0.040. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (14) to 0.030, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (14) may be set to 0.025, or further to 0.020.

In the optical system LS (zoom optical system) according to the second embodiment, preferably, the negative lens satisfies the following conditional expression (15),

0.50<fN3/fGa<7.00   (15)

where fN3: the focal length of the negative lens, and

fGa: a focal length of the object-side negative lens group.

The conditional expression (15) defines an appropriate relationship between the focal length of the negative lens and the focal length of the object-side negative lens group. By satisfying the conditional expression (15), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (15) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (15) to 0.55, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (15) may be set to 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00 or 1.05, or further to 1.10.

By setting the upper limit value of the conditional expression (15) to 6.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (15) may be set to 6.20, 5.50, 5.00, 4.50, 4.00, 3.80, 3.30, 3.00 or 2.80, or further to 2.30.

In the optical system LS (zoom optical system) according to the second embodiment, preferably, the object-side negative lens group satisfies the following conditional expression (16),

0.20<(−fGa)/f<3.50   (16)

where fGa: a focal length of the object-side negative lens group, and

f: a focal length of the zoom optical system LS (zoom optical system) in a wide angle end state.

The conditional expression (16) defines an appropriate relationship between the focal length of the object-side negative lens group and the focal length of the optical system LS (zoom optical system). By satisfying the conditional expression (16), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (16) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (16) to 0.25, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (16) maybe set to 0.30, 0.35, 0.40, 0.45 or 0.50, or further to 0.55.

By setting the upper limit value of the conditional expression (16) to 3.30, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (16) may be set to 3.00, 2.80, 2.65, 2.45 or 2.15, or further to 2.00.

In the optical system LS (zoom optical system) according to the second embodiment, the negative lens may satisfy the following conditional expression (13-1),

0.555<θgFN3.   (13-1)

The conditional expression (13-1) is an expression similar to the conditional expression (13), and can exert advantageous effects similar to those of the conditional expression (13). By setting the lower limit value of the conditional expression (13-1) to 0.556, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (13-1) to 0.557.

In the optical system LS (zoom optical system) according to the second embodiment, the negative lens may satisfy the following conditional expression (14-1),

0.010<θgFN3−(0.6418−0.00168×νdN3).   (14-1)

The conditional expression (14-1) is an expression similar to the conditional expression (14), and can exert advantageous effects similar to those of the conditional expression (14). By setting the lower limit value of the conditional expression (14-1) to 0.011, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (14-1) to 0.012.

Note that the upper limit value of the conditional expression (14-1) may be set to less than 0.030. Accordingly, advantageous effects similar to those of the conditional expression (14) can be achieved. In this case, by setting the upper limit value of the conditional expression (14-1) to 0.028, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (14-1) may be set to 0.025 or 0.023, or further to 0.020.

In the optical system LS (zoom optical system) according to the second embodiment, preferably, the negative lens satisfies the following conditional expression (17),

DN3>0.400 [mm]  (17)

where DN3: a thickness of the negative lens on an optical axis.

The conditional expression (17) appropriately defines the thickness of the negative lens on the optical axis. By satisfying the conditional expression (17), the various aberrations, such as the coma aberration, the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), can be favorably corrected.

If the corresponding value of the conditional expression (17) falls outside of the range, the correction of the various aberrations, such as the coma aberration and the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), becomes difficult. By setting the lower limit value of the conditional expression (17) to 0.450 [mm], the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (17) may be set to 0.490 [mm], 0.550 [mm], 0.580 [mm], 0.650 [mm], 0.680 [mm], 0.750 [mm], 0.800 [mm], 0.850 [mm] , 0.880 [mm], 0.950 [mm], 0.980 [mm], 1.050 [mm], 1.100 [mm], 1.140 [mm] or 1.250 [mm], or further to 1.350 [mm].

In the optical system LS (zoom optical system) according to the second embodiment, preferably, the negative lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the negative lens. Accordingly, even in the case where the negative lens has a lens surface in contact with air (i.e., a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other), it is preferable because variation in optical characteristics due to temperature is small.

In the optical system LS (zoom optical system) according to the second embodiment, at least one lens surface of an object-side lens surface and an image-side lens surface of the negative lens is in contact with air. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the negative lens. Accordingly, even in a case where a lens surface of the negative lens is in contact with air, it is preferable because the variation in optical characteristics due to temperature is small.

In the optical system LS (zoom optical system) according to the second embodiment, it is desirable that the negative lens be a glass lens. The secular change of the negative lens that is a glass lens is smaller than that of a resin lens. Accordingly, it is preferable because the variation in optical characteristics due to temperature is small.

Subsequently, referring to FIG. 25, a method for manufacturing the optical system LS (zoom optical system) according to the second embodiment is schematically described. First, a plurality of lens groups including lens groups having negative refractive powers are arranged (step ST11). The configuration is made so that the distance between lens groups adjacent to each other changes upon zooming (step ST12). Each lens is arranged in the lens barrel so that the object-side negative lens group disposed closest to the object among the lens groups having negative refractive powers includes the negative lens satisfying the conditional expressions (11) to (14) and the like (step ST13). According to such a manufacturing method, the zoom optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected can be manufactured.

EXAMPLES

Optical systems LS according to Examples of each embodiment are described with reference to the drawings. Note that Examples corresponding to the first embodiment are First to Eleventh Examples, and Examples corresponding to the second embodiment are Second to Eleventh Examples. FIGS. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 and 21 are sectional views showing the configurations and refractive power allocations of optical systems LS {LS (1) to LS (11)} according to First to Eleventh Examples. In the sectional views of the optical systems LS(1) to LS(11) according to First to Eleventh Examples, the moving direction upon focusing by each focusing lens group from the infinity to a short-distance object is indicated by an arrow accompanied by characters “FOCUSING”. The optical system LS(2) to (11) according to Second to Eleventh Examples are zoom optical systems that perform zooming by changing the distance between lens groups adjacent to each other. In the sectional views of the optical systems LS(2) to LS(11) according to Second to Eleventh Examples, the moving direction of each lens group along the optical axis upon zooming from the wide angle end state (W) to the telephoto end state (T) is indicated by an arrow.

In FIGS. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 and 21, each lens group is represented by a combination of a symbol G and a numeral, and each lens is represented by a combination of a symbol L and a numeral. In this case, to prevent complication due to increase in the types and numbers of symbols and numerals, the lens groups and the like are represented using the combinations of symbols and numerals independently on an Example-by-Example basis. Accordingly, even when the same combination of a symbol and a numeral is used among Examples, such usage does not mean the same configuration.

Tables 1 to 11 are shown below. Among the drawings, Table 1 is a table showing each data item in First Example, Table 2 is that in Second Example, Table 3 is that in Third Example, Table 4 is that in Fourth Example, Table 5 is that in Fifth Example, Table 6 is that in Sixth Example, Table 7 is that in Seventh Example, Table 8 is that in Eighth Example, Table 9 is that in Ninth Example, Table 10 is that in Tenth Example, and Table 11 is that in Eleventh Example. In each Example, as targets of calculation of aberration characteristics, d-line (wavelength λ=587.6 nm), g-line (wavelength λ=435.8 nm), C-line (wavelength λ=656.3 nm), and F-line (wavelength λ=486.1 nm) are selected.

In the table of [General Data], f indicates the focal length of the entire lens system, FNO indicates the f-number, 2ω indicates the angle of view (the unit is ° (degrees), and ω is the half angle of view), and Y indicates the image height. TL indicates a distance obtained by adding BF to the distance from the lens foremost surface to the lens last surface on the optical axis upon focusing on infinity. BF indicates the distance (back focus) from the lens last surface to the image surface I on the optical axis upon focusing on infinity. fF indicates the focal length of the front group, and fR indicates the focal length of the rear group. Note that in a case where the optical system is a zoom optical system, these values are indicated for each of zoom states at the wide-angle end (W), the intermediate focal length (M) and the telephoto end (T).

In the table of [Lens Data], Surface Number indicates the order of the optical surface from the object side along the direction in which the ray travels, R indicates the radius of curvature (the surface whose center of curvature resides on the image side is regarded to have a positive value) of each optical surface, D indicates the surface distance which is the distance to the next lens surface (or the image surface) from each optical surface on the optical axis, nd is the refractive index of the material of the optical member for d-line, νd indicates the Abbe number of the material of the optical member with respect to d-line, and θgF indicates the partial dispersion ratio of the material of the optical member. The radius of curvature “∞” indicates a plane or an opening. (Aperture Stop S) indicates an aperture stop S. The description of the air refractive index nd=1.00000 is omitted. In a case where the optical surface is an aspherical surface, the surface number is assigned * symbol, and the field of the radius of curvature R indicates the paraxial radius of curvature.

The refractive index of the optical member for g-line (wavelength λ=435.8 nm) is indicated by ng. The refractive index of the optical member for F-line (wavelength λ=486.1 nm) is indicated by nF. The refractive index of the optical member for C-line (wavelength λ=656.3 nm) is indicated by nC. Here, the partial dispersion ratio θgF of the material of the optical member is defined by the following expression (A).

θgF=(ng−nF)/(nF−nC).   (A)

In the table of [Aspherical Data], the shape of the aspherical surface indicated in [Lens Data] is indicated by the following expression (B). X(y) indicates the distance (sag amount) from the tangent plane at the vertex of the aspherical surface to the position on the aspherical surface at the height y along the optical axis direction. R indicates the radius of curvature (paraxial radius of curvature) of the reference spherical surface. κ indicates the conic constant. Ai indicates the i-th aspherical coefficient. “E-n” indicates “×10^(−n)”. For example, 1.234E−05=1.234×10⁻⁵. Note that the second-order aspherical coefficient A2 is zero, and the description thereof is omitted.

X(y)=(y ² /R)/{1+(1−κ×y ² /R ²)^(1/2)}+A4×y ⁴ +A6×y ⁶ +A8×y ⁸ +A10×y ¹⁰ +A12×y ¹².   (B)

In a case where the optical system is not a zoom optical system, f indicates the focal length of the entire lens system, and β indicates the photographing magnification, as [Variable Distance Data on Short-Distance Photographing]. The table of [Variable Distance Data on Short-Distance Photographing] indicates the surface distance at the surface number where the surface distance is “Variable” in [Lens Data] corresponding to each focal length and photographing magnification.

In the case where the optical system is the zoom optical system, the surface distance at the surface number where the surface distance is “Variable” in [Lens Data] corresponding to each of zooming states at the wide angle end (W), the intermediate focal length (M) and the telephoto end (T) are indicated as [Variable Distance Data on Zoom Photographing].

The table of [Lens Group Data] shows the first surface (the surface closest to the object) and the focal length of each lens group.

The table of [Conditional Expression Corresponding Value] shows the value corresponding to each conditional expression.

Hereinafter, at all the data values, the listed focal length f, the radius of curvature R, the surface distance D, other lengths and the like are represented with “mm” if not otherwise specified. However, even after subjected to proportional scaling in or out, the optical system can achieve equivalent optical performance. Accordingly, the representation is not limited thereto.

The descriptions of the tables so far are common to all the Examples. Redundant descriptions are hereinafter omitted.

First Example

First Example is described with reference to FIGS. 1 and 2A, 2B and 2C and Table 1. FIG. 1 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to First Example. The optical system LS(1) according to First Example consists of, in order from the object: a first lens group G1 having a positive refractive power; and a second lens group G2 having a positive refractive power. Upon focusing from the infinity object to the short-distant (finite distant) object, the second lens group G2 moves toward the object along the optical axis. The aperture stop S is disposed in the first lens group G1. A sign (+) or (−) assigned to each lens group symbol indicates the refractive power of each lens group. This indication similarly applies to all the following Examples.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L1 having a convex surface facing the object; a positive meniscus lens L2 having a convex surface facing the object; a negative meniscus lens L3 having a convex surface facing the object; negative meniscus lens L4 having a convex surface facing an object; a cemented lens consisting of a negative meniscus lens L5 having a convex surface facing an object, and a positive meniscus lens L6 having a convex surface facing the object; a biconvex positive lens L7; a cemented lens consisting of a positive meniscus lens L8 having a concave surface facing the object, and a biconcave negative lens L9; and a biconvex positive lens L10. An aperture stop S is disposed between a positive lens L7 and a positive meniscus lens L8 (of the cemented lens) in the first lens group G1. In this Example, the negative meniscus lens L4 of the first lens group G1 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like.

The second lens group G2 consists of, in order from the object: a positive meniscus lens L21 having a concave surface facing the object; and a cemented lens consisting of a positive meniscus lens L22 having a concave surface facing the object, and a negative meniscus lens L23 having a concave surface facing the object. An image surface I is disposed on the image side of the second lens group G2. The positive meniscus lens L21 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L1, the positive meniscus lens L2, the negative meniscus lens L3, the negative meniscus lens L4, the cemented lens consisting of the negative meniscus lens L5 and the positive meniscus lens L6, and the positive lens L7 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the positive meniscus lens L8 and the negative lens L9, the positive lens L10, the positive meniscus lens L21, the cemented lens consisting of the positive meniscus lens L22 and the negative meniscus lens L23 having a concave surface facing the object constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 1 lists values of data on the optical system according to First Example.

TABLE 1 [General Data] f 18.427 FNO 2.925 2ω 100.785 Y 21.700 TL 102.549 BF 37.769 fF 332.090 fR 33.732 [Lens Data] Surface Number R D nd νd θgF  1 47.34020 1.800 1.84042 43.34 0.5621  2 25.82350 4.000  3 37.48750 6.900 1.65160 58.54 0.5436  4 363.46330 0.100  5 22.64200 1.300 1.79668 45.37 0.5592  6 12.39830 3.900  7 31.60920 1.150 1.62731 59.30 0.5584  8 13.95370 2.500  9 45.71850 1.000 1.62041 60.12 0.5417 10 9.13380 3.000 1.59507 35.51 0.5913 11 15.12450 1.000 12 23.56840 12.300  1.69911 27.83 0.6107 13 −23.38780 0.700 14 ∞ 1.850 (Aperture Stop S) 15 −38.67920 4.000 1.62588 35.70 0.5847 16 −13.61320 1.200 1.86074 23.01 0.6195 17 72.75580 1.000 18 78.27770 3.400 1.66755 41.96 0.5745 19 −15.39400 D19(Variable) 20 −33.19360 2.000 1.51680 64.12 0.5360 21* −30.04030 1.200 22 −26.81950 5.000 1.59319 67.87 0.5435 23 −13.53970 1.800 1.86074 23.01 0.6195 24 −16.60140 BF [Aspherical Surface Data] 21st Surface κ = 1.000, A4 = 5.0910E−05, A6 = 1.2580E−07 A8 = −9.2250E−10, A10 = 5.5330E−12, A12 = 0.0000E+00 [Variable distance data on short-distance photographing] Upon focusing Upon focusing Upon focusing on an intermediate on a short- on infinity distance object distance object f = 18.427 β = −0.033 β = −0.110 D19 3.681 2.861 1.035 [Lens Group Data] Group First surface Focal length G1 1 36.330 G2 20 61.320 [Conditional Expression Corresponding Value] <Negative meniscus lens L4(fN1 = −40.849)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.016 Conditional Expression(2)νdN1 = 59.30 Conditional Expression(3), (3-1)θgFN1 = 0.5584 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0162 Conditional Expression(5)(−fN1)/fF = 0.123 Conditional Expression(6)(−fN1)/f = 2.217 Conditional Expression(7)DN1 = 1.150

FIG. 2A shows various aberration graphs of the optical system according to First Example upon focusing on infinity. FIG. 2B shows various aberration graphs of the optical system according to First Example upon focusing on an intermediate distant object. FIG. 2C shows various aberration graphs of the optical system according to First Example upon focusing on a short-distant (very short distance) object. In each graph upon focusing on infinity, FNO indicates the f-number, and Y indicates the image height. In each aberration graph upon focusing on the intermediate distant object or focusing on the short distant object, NA indicates the numerical aperture, and Y indicates the image height. The spherical aberration graph indicates the value of the f-number or the numerical aperture that corresponds to the maximum diameter. The astigmatism graph and the distortion graph each indicate the maximum value of the image height. The coma aberration graph indicates the value of the corresponding image height. d indicates d-line (wavelength λ=587.6 nm), g indicates g-line (wavelength λ=435.8 nm), C indicates C-line (wavelength λ=656.3 nm), and F indicates F-line (wavelength λ=486.1 nm). In the astigmatism graph, a solid line indicates a sagittal image surface, and a broken line indicates a meridional image surface. Note that also in the following aberration graphs in each Example, symbols similar to those in this Example are used. Redundant description is omitted.

The various aberration graphs show that the optical system according to First Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Second Example

Second Example is described with reference to FIGS. 3 and 4A, 4B and 4C and Table 2. FIG. 3 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Second Example. The optical system LS(2) according to Second Example consists of, in order from the object: a first lens group G1 having a negative refractive power; a second lens group G2 having a positive refractive power; a third lens group G3 having a negative refractive power; and a fourth lens group G4 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fourth lens groups G1 to G4 move in directions indicated by arrows in FIG. 3. The aperture stop S is disposed in the second lens group G2.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L11 having a convex surface facing the object; a negative meniscus lens L12 having a convex surface facing the object; a biconcave negative lens L13; and a biconvex positive lens L14. In this Example, the negative lens L13 of the first lens group G1 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the first lens group G1 corresponds to an object-side negative lens group, and the negative lens L13 of the first lens group G1 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like. The negative meniscus lens L11 is a hybrid type lens that includes a lens main body made of glass, and a resin layer provided on the image-side surface of the lens main body. The image-side surface of the resin layer is an aspherical surface. The negative meniscus lens L11 is a composite type aspherical surface lens. In [Lens Data] described later, the surface number 1 indicates the object-side surface of the lens main body, the surface number 2 indicates the image-side surface of the lens main body and the object-side surface of the resin layer (a surface on which both the elements are in contact), and the surface number 3 indicates the image-side surface of the resin layer. The negative meniscus lens L12 is a hybrid type lens that includes a lens main body made of glass, and a resin layer provided on the object-side surface of the lens main body. The object-side surface of the resin layer is an aspherical surface. The negative meniscus lens L12 is a composite type aspherical surface lens. In [Lens Data] described later, the surface number 4 indicates the object-side surface of the resin layer, the surface number 5 indicates the image-side surface of the resin layer and the object-side surface of the lens main body (a surface on which both the elements are in contact), and the surface number 6 indicates the image-side surface of the lens main body.

The second lens group G2 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L21 and a biconcave negative lens L22; a positive meniscus lens L23 having a concave surface facing the object; and a cemented lens consisting of the biconvex positive lens L24 and the negative meniscus lens L25 having a concave surface facing the object. An aperture stop S is disposed between the positive meniscus lens L23 and the positive lens L24 (of the cemented lens) of the second lens group G2. The positive meniscus lens L23 of the second lens group G2 constitutes a vibration-proof lens group (partial group) that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I).

The third lens group G3 consists of, in order from the object: a biconcave negative lens L31; and a positive meniscus lens L32 having a convex surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the third lens group G3 moves toward the image along the optical axis.

The fourth lens group G4 consists of, in order from the object: a positive meniscus lens L41 having a concave surface facing the object; and a cemented lens consisting of the biconcave negative lens L42 and the biconvex positive lens L43. An image surface I is disposed on the image side of the fourth lens group G4. The positive meniscus lens L41 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L11, the negative meniscus lens L12, the negative lens L13, the positive lens L14, the cemented lens consisting of the positive lens L21 and the negative lens L22; and the positive meniscus lens L23 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the positive lens L24 and the negative meniscus lens L25, the negative lens L31, the positive meniscus lens L32, the positive meniscus lens L41, and the cemented lens consisting of the negative lens L42 and the positive lens L43 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 2 lists values of data on the optical system according to Second Example. Note that the eleventh surface is a virtual surface.

TABLE 2 [General Data] Zooming ratio = 1.881 W M T f 10.310 14.992 19.394 FNO 4.625 5.233 5.828 2ω 55.344 43.833 36.393 Y 14.250 14.250 14.250 TL 127.176 118.440 118.247 BF 38.107 45.676 53.470 fF −25.207 −22.363 −21.191 fR 35.566 35.133 34.930 [Lens Data] Surface Number R D nd νd θgF  1 72.21520 2.400 1.77250 49.62 0.5518  2 18.07840 0.200 1.56093 36.64 0.5931  3* 12.80980 13.500   4* 38.72530 0.200 1.55389 38.09 0.5928  5 33.77930 1.500 1.80610 40.97 0.5688  6 15.49570 6.413  7 −222.76580 1.300 1.68348 54.80 0.5501  8 47.03490 0.100  9 25.72760 4.150 1.71736 29.57 0.6036 10 −234.96610 D10(Variable) 11 ∞ 1.100 12 24.59470 2.550 1.72825 28.38 0.6069 13 −16.15400 0.800 1.91082 35.25 0.5824 14 27.17750 1.920 15 −248.17450 1.580 1.51680 63.88 0.5360 16 −25.45380 1.455 17 ∞ 1.802 (Aperture Stop S) 18 21.50780 3.280 1.53172 48.78 0.5622 19 −15.09980 0.900 1.91082 35.25 0.5824 20 −23.42430 D20(Variable) 21 −112.18850 0.800 1.91082 35.25 0.5824 22 28.22450 0.697 23 18.60970 1.830 1.51680 63.88 0.5360 24 78.16100 D24(Variable) 25 −60.82670 1.350 1.53110 55.91 0.5684 26* −34.60170 0.600 27 −134.59820 0.800 1.91082 35.25 0.5824 28 21.04650 5.600 1.48749 70.31 0.5291 29 −15.26510 BF [Aspherical Surface Data] 3rd Surface κ = 0.039, A4 = −1.10E−05, A6 = −2.98E−08 A8 = 1.59E−10, A10 = 2.68E−13, A12 = 0.00E+00 4th Surface κ = 0.208,A4 = −3.60E−06, A6 = 8.87E−08 A8 = 2.10E−10, A10 = −2.30E−13, A12 = 0.00E+00 26th Surface κ = 1.000, A4 = 5.66E−05, A6 = 5.08E−08 A8 = −2.05E−09, A10 = 3.50E−11, A12 = 0.00E+00 [Variable distance data on zoom photographing] W M T D10 25.062 8.757 0.770 D20 1.457 2.644 3.179 D24 5.723 4.536 4.001 [Lens Group Data] Group First surface Focal length G1 1 −16.381 G2 11 24.075 G3 21 −53.290 G4 25 70.213 [Conditional Expression Corresponding Value] <Negative lens L13(fN1 = −56.709)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = −2.250 Conditional Expression(6)(−fN1)/f = 5,500 Conditional Expression(7)DN1 = 1.300 <Negative lens L13(fN3 = −56.709)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12) νdN3 = 54.80 Conditional Expression(13), (13-1) θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN3 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15) fN3/fGa = 3.462 Conditional Expression(16) (−fGa)/f = 1.589 Conditional Expression(17)DN3 = 1.300

FIG. 4A shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the wide angle end state. FIG. 4B shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the intermediate focal length state. FIG. 4C shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Second Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Third Example

Third Example is described with reference to FIGS. 5 and 6A, 6B and 6C and Table 3. FIG. 5 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Third Example. The optical system LS(3) according to Third Example consists of, in order from the object: a first lens group G1 having a negative refractive power; a second lens group G2 having a positive refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 5. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L11 having a convex surface facing the object; a negative meniscus lens L12 having a convex surface facing the object; a biconcave negative lens L13; and a biconvex positive lens L14. In this Example, the negative meniscus lens L11, the negative meniscus lens L12 and the negative lens L13 of the first lens group G1 correspond to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the first lens group G1 corresponds to the object-side negative lens group, and the negative meniscus lens L11, the negative meniscus lens L12 and the negative lens L13 of the first lens group G1 correspond to a negative lens that satisfies the conditional expressions (11) to (14) and the like. The negative meniscus lens L11 has an image-side lens surface that is an aspherical surface. The negative meniscus lens L12 has an image-side lens surface that is an aspherical surface.

The second lens group G2 consists of, in order from the object: a positive meniscus lens L21 having a convex surface facing the object; and a cemented lens consisting of a negative meniscus lens L22 having a convex surface facing the object, and a positive meniscus lens L23 having a convex surface facing the object. The aperture stop S is disposed adjacent to the image side of the positive meniscus lens L23, and moves with the second lens group G2 upon zooming.

The third lens group G3 consists of, in order from the object: a cemented lens consisting of a biconcave negative lens L31 and a biconvex positive lens L32; and a biconvex positive lens L33. The positive lens L32 has an image-side lens surface that is an aspherical surface.

The fourth lens group G4 consists of a biconcave negative lens L41. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of a positive meniscus lens L51 having a concave surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The positive meniscus lens L51 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L11, the negative meniscus lens L12, the negative lens L13, the positive lens L14, the positive meniscus lens L21, and the cemented lens consisting of the negative meniscus lens L22 and the positive meniscus lens L23 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the negative lens L31 and the positive lens L32, the positive lens L33, the negative lens L41, and the positive meniscus lens L51 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 3 lists values of data on the optical system according to Third Example.

TABLE 3 [General Data] Zooming ratio = 2.018 W M T f 14.420 20.000 29.100 FNO 4.073 4.072 4.066 2ω 115.788 91.602 67.988 Y 20.500 20.500 20.500 TL 121.803 110.314 103.827 BF 15.000 23.093 30.403 fF 12.336 18.020 29.688 fR −249.182 −357.800 −1948.200 [Lens Data] Surface Number R D nd νd θgF  1 92.62990 3.000 1.68348 54.80 0.5501  2* 15.67070 4.579  3 28.37140 2.900 1.68348 54.80 0.5501  4* 21.12170 12.704   5 −37.55490 1.900 1.68348 54.80 0.5501  6 88.75380 0.100  7 98.47090 5.412 1.86109 34.82 0.5864  8 −53.58090 D8(Variable)  9 20.49420 4.232 1.59349 67.00 0.5358 10 164.24190 3.859 11 16.69960 1.200 1.88300 40.66 0.5668 12 8.68950 4.536 1.52748 56.00 0.5481 13 180.51560 2.500 14 ∞ D14(Variable) (Aperture Stop S) 15 −357.35260 1.100 1.81600 46.59 0.5567 16 14.59730 3.507 1.49782 82.57 0.5386 17* −561.45740 1.192 18 36.97580 6.029 1.49782 82.57 0.5386 19 −12.85510 D19(Variable) 20 −20.05630 1.000 1.55199 62.60 0.5377 21 48.74520 D21(Variable) 22 −64.12910 1.200 1.51680 63.88 0.5360 23* −53.18510 BF [Aspherical Surface Data] 2nd Surface κ = 0.000, A4 = −9.16E−07, A6 = 3.00E−08 A8 = −1.16E−10, A10 = 1.53E−13, A12 = 0.00E+00 4th Surface κ = 0.000, A4 = 3.15E−05, A6 = −2.15E−08 A8 = 4.46E−10, A10 = −1.10E−12, A12 = 2.22E−15 17th Surface κ = 1.000, A4 = 5.91E−05, A6 = 1.04E−07 A8 = 3.02E−09, A10 = −4.09E−11, A12 = 0.00E+00 23rd Surface κ = 1.000, A4 = 3.06E−05, A6 = 2.73E−08 A8 = −4.72E−11, A10 = 7.08E−13, A12 = 0.00E+00 [Variable distance data on zoom photographing] W M T D8 33.229 16.105 1.500 D14 2.125 2.115 2.279 D19 2.000 2.982 4.774 D21 8.500 5.069 3.922 [Lens Group Data] Group First surface Focal length G1 1 −23.700 G2 9 28.300 G3 15 28.700 G4 20 −25.600 G5 22 581.300 [Conditional Expression Corresponding Value] <Negative meniscus lens L11(fN1 = −28.041)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = 2.273 Conditional Expression(6)(−fN1)/f = 1.945 Conditional Expression(7)DN1 = 3.000 <Negative meniscus lens L12(fN1 = −144.389)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = 11.705 Conditional Expression(6)(−fN1)/f = 10.013 Conditional Expression(7)DN1 = 2.900 <Negative lens L13(fN1 = −38.375)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = 3.111 Conditional Expression(6)(−fN1)/f = 2.661 Conditional Expression(7)DN1 = 1.900 <Negative meniscus lens L11(fN3 = −28.041)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 1.183 Conditional Expression(16)(−fGa)/f = 1.644 Conditional Expression(17)DN3 = 3.000 <Negative meniscus lens L12(fN3 = −144.389)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 6.092 Conditional Expression(16)(−fGa)/f = 1.644 Conditional Expression(17)DN3 = 2.900 <Negative lens L13(fN3 = −38.375)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 1.619 Conditional Expression(16)(−fGa)/f = 1.644 Conditional Expression(17)DN3 = 1.900

FIG. 6A shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the wide angle end state. FIG. 6B shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the intermediate focal length state. FIG. 6C shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Third Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Fourth Example

Fourth Example is described with reference to FIGS. 7 and 8A, 8B and 8C and Table 4. FIG. 7 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Fourth Example. The optical system LS(4) according to Fourth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 7. The aperture stop S is disposed in the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L22; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the second lens group G2 moves toward the object along the optical axis. In this Example, the negative lens L22 and the negative meniscus lens L24 of the second lens group G2 correspond to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative lens L22 and the negative meniscus lens L24 of the second lens group G2 correspond to a negative lens that satisfies the conditional expressions (11) to (14) and the like. The negative meniscus lens L21 has an object-side lens surface that is an aspherical surface. The negative meniscus lens L24 has an image-side lens surface that is an aspherical surface.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a negative meniscus lens L32 having a convex surface facing the object, and a biconvex positive lens L33; and a biconvex positive lens L34. An aperture stop S is disposed between the positive lens L31 and the negative meniscus lens L32 (of the cemented lens) of the third lens group G3.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a positive meniscus lens L41 having a concave surface facing the object, and a negative meniscus lens L42 having a concave surface facing the object; and a biconcave negative lens L43.

The fifth lens group G5 consists of, in order from the object: a biconvex positive lens L51; and a cemented lens consisting of a biconvex positive lens L52, and a biconcave negative lens L53. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L22, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, the negative meniscus lens L24, and the positive lens L31 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the negative meniscus lens L32 and the positive lens L33, the positive lens L34, the cemented lens consisting of the positive meniscus lens L41 and the negative meniscus lens L42, the negative lens L43, the positive lens L51, and the cemented lens consisting of the positive lens L52 and the negative lens L53 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 4 lists values of data on the optical system according to Fourth Example.

TABLE 4 [General Data] Zooming ratio = 4.708 W M T f 24.721 50.047 116.396 FNO 4.061 4.089 4.154 2ω 86.421 43.929 19.678 Y 21.600 21.600 21.600 TL 147.200 161.419 192.191 BF 32.363 42.319 54.282 fF 130.487 −421.097 −283.255 fR 64.879 65.108 63.558 [Lens Data] Surface Number R D nd νd θgF  1 200.00000 1.200 1.80090 23.50 0.6172  2 104.14190 7.444 1.49782 82.57 0.5138  3 −307.28920 0.100  4 57.34930 5.648 1.59593 53.79 0.5519  5 128.95340  D5(Variable)  6* 71.49190 1.050 1.90795 33.46 0.5892  7 17.08640 6.423  8 −51.62780 1.200 1.68348 54.80 0.5501  9 41.08490 0.100 10 39.55730 6.320 1.85168 23.41 0.6176 11 −44.35580 0.786 12 −28.66820 1.200 1.68348 54.80 0.5501 13* −263.12090 D13(Variable) 14 43.24040 3.754 1.61063 51.59 0.5558 15 −90.35860 0.100 16 ∞ 0.100 (Aperture Stop S) 17 39.53750 1.200 1.93504 24.35 0.6140 18 18.91420 5.342 1.49801 82.47 0.5140 19 −147.86550 0.100 20 48.40300 2.948 1.59761 53.52 0.5524 21 −295.39370 D21(Variable) 22 −35.36590 3.889 1.92286 20.88 0.6287 23 18.36590 1.200 1.67449 44.60 0.5682 24 −175.62470 2.444 25 −58.08520 1.200 1.69893 42.67 0.5717 26 870.88710 D26(Variable) 27* 157.96590 5.992 1.49782 82.57 0.5138 28 −24.48700 0.100 29 65.91830 7.455 1.69249 43.15 0.5709 30 −25.49740 5.017 1.88686 29.29 0.5989 31 75.48320 BF [Aspherical Surface Data] 6th Surface k = 1.000, A4 = −2.91E−06, A6 = −1.03E−08 A8 = 2.57E−11, A10 = −6.80E−14, A12 = 0.00E+00 13th Surface κ = 1.000, A4 = −1.06E−05, A6 = −1.03E−08 A8 = −3.07E−11, A10 = 0.00E+00, A12 = 0.00E+00 27th Surface κ = 1.000, A4−1.53E−05, A6 = 9.72E−09 A8 = −2.61E−11, A10 = 3.55E−14, A12 = 0.00E+00 [Variable distance data on zoom photographing] W M T D5 1.500 19.695 47.327 D13 24.246 10.310 1.500 D21 2.853 9.990 14.771 D26 13.928 6.794 2.000 [Lens Group Data] Group First surface Focal length G1 1 115.700 G2 6 −18.700 G3 14 27.100 G4 22 −46.200 G5 27 54.900 [Conditional Expression Corresponding Value] <Negative lens L22(fN1 = −33.299)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = 0.255 Conditional Expression(6)(−fN1)/f = l.347 Conditional Expression(7)DN1 = 1.200 <Negative meniscus lens L24(fN1 = −47.172)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = 0.362 Conditional Expression(6)(−fN1)/f = 1.908 Conditional Expression(7)DN1 = 1.200 <Negative lens L22(fN3 = −33.299)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418− 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 1.781 Conditional Expression(16)(−fGa)/f = 0.756 Conditional Expression(17)DN3 = 1.200 <Negative meniscus lens L24(fN3 = −47.172)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 2.523 Conditional Expression(16)(−fGa)/f = 0.756 Conditional Expression(17)DN3 = 1.200

FIG. 8A shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the wide angle end state. FIG. 8B shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the intermediate focal length state. FIG. 8C shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Fourth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Fifth Example

Fifth Example is described with reference to FIGS. 9 and 10A, 10B and 10C and Table 5. FIG. 9 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Fifth Example. The optical system LS(5) according to Fifth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; and a fifth lens group G5 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the second lens groups G2 and the fourth lens group G4 move in directions indicated by arrows in FIG. 9. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a positive meniscus lens L23 having a convex surface facing the object; and a biconcave negative lens L24. In this Example, the negative meniscus lens L21, the negative lens L22 and the negative lens L24 of the second lens group G2 correspond to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to the object-side negative lens group, and the negative meniscus lens L21, the negative lens L22 and the negative lens L24 of the second lens group G2 correspond to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a plano-convex positive lens L32 having a convex surface facing the object; a positive meniscus lens L33 having a convex surface facing the object; a biconcave negative lens L34; and a cemented lens consisting of a biconvex positive lens L35, and a biconcave negative lens L36. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming.

The fourth lens group G4 consists of, in order from the object: a biconvex positive lens L41; and a cemented lens consisting of a negative meniscus lens L42 having a convex surface facing the object, and a positive meniscus lens L43 having a convex surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the object along the optical axis.

The fifth lens group G5 consists of, in order from the object: a negative meniscus lens L51 having a convex surface facing the object; a cemented lens consisting of a biconvex positive lens L52, and a biconcave negative lens L53; a plano-concave negative lens L54 having a concave surface facing the image; a biconvex positive lens L55; and a positive meniscus lens L56 having a convex surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The cemented lens consisting of the positive lens L52 and the negative lens L53, and the negative lens L54 of the fifth lens group G5 constitute a vibration-proof lens group (partial group) that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I).

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive meniscus lens L23, and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the positive lens L32, the positive meniscus lens L33, the negative lens L34, the cemented lens consisting of the positive lens L35 and the negative lens L36, the positive lens L41, the cemented lens consisting of the negative meniscus lens L42 and the positive meniscus lens L43, the negative meniscus lens L51, the cemented lens consisting of the positive lens L52 and the negative meniscus lens L53, the negative lens L54, the positive lens L55, and the positive meniscus lens L56 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 5 lists values of data on the optical system according to Fifth Example.

TABLE 5 [General Data] Zooming ratio = 2.745 W M T f 71.400 140.000 196.000 FNO 2.865 2.937 2.862 2ω 33.666 17.094 12.198 Y 21.600 21.600 21.600 TL 245.880 245.880 245.880 BF 53.818 53.818 53.818 fF −86.769 −153.380 −238.187 fR 67.044 63.889 67.044 [Lens Data] Surface Number R D nd νd θgF 1 120.99680 2.800 1.95000 29.37 0.6002 2 87.12840 9.900 1.49782 82.57 0.5386 3 −1437.70340 0.100 4 97.36390 7.700 1.45600 91.37 0.5342 5 657.25840  D5(Variable) 6 73.32110 2.400 1.68348 54.80 0.5501 7 33.43260 10.250  8 −134.27600 2.000 1.62731 59.30 0.5584 9 104.31770 2.000 10 55.93640 4.400 1.84666 23.78 0.6192 11 193.35670 3.550 12 −72.87930 2.200 1.62731 59.30 0.5584 13 610.02530 D13(Variable) 14 ∞ 2.500 (Aperture Stop S) 15 667.50610 3.700 1.83481 42.73 0.5648 16 −127.34870 0.200 17 91.74030 3.850 1.59319 67.90 0.5440 18 ∞ 0.200 19 52.70200 4.900 1.49782 82.57 0.5386 20 340.98300 2.120 21 −123.54810 2.200 2.00100 29.13 0.5995 22 172.97240 4.550 23 104.97670 5.750 1.90265 35.72 0.5804 24 −70.95230 2.200 1.58144 40.98 0.5763 25 42.96180 D25(Variable) 26 69.69710 4.800 1.49782 82.57 0.5386 27 −171.29750 0.100 28 43.33010 2.000 1.95000 29.37 0.6002 29 28.62160 5.550 1.59319 67.90 0.5440 30 175.11530 D30(Variable) 31 59.19620 1.800 1.80400 46.60 0.5575 32 33.42540 5.150 33 127.38170 3.350 1.84666 23.78 0.6192 34 −127.38220 1.600 1.68348 54.80 0.5501 35 43.09820 2.539 36 ∞ 1.600 1.95375 32.32 0.5901 37 71.19380 3.750 38 107.03200 3.850 1.59319 67.90 0.5440 39 −166.05150 0.150 40 49.83700 3.900 1.71999 50.27 0.5527 41 161.11230 BF [Variable distance data on zoom photographing] W M T D5 2.882 35.671 50.879 D13 50.300 17.511 2.303 D25 17.270 14.466 17.270 D30 2.000 4.804 2.000 [Lens Group Data] Group First surface Focal length G1 1 143.763 G2 6 −45.569 G3 14 90.760 G4 26 60.061 G5 31 −112.026 [Conditional Expression Corresponding Value] <Negative meniscus lens L21(fN1 = −92.166)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = −1.062 Conditional Expression(6)(−fN1)/f = 1.291 Conditional Expression(7)DN1 = 2.400 <Negative lens L22 (fN1 = −93.285)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.016 Conditional Expression(2)νdN1 = 59.30 Conditional Expression(3), (3-1)θgFN1 = 0.5584 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0162 Conditional Expression(5)(−fN1)/fF = −1.075 Conditional Expression(6)(−fN1)/f = 1.307 Conditional Expression(7)DN1 = 2.000 <Negative lens L24(fN1 = −103.650)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.016 Conditional Expression(2)νdN1 = 59.30 Conditional Expression(3), (3-1)θgFN1 = 0.5584 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0162 Conditional Expression(5)(−fN1)/fF = −1.195 Conditional Expression(6)(−fN1)/f = 1.452 Conditional Expression(7)DN1 = 2.200 <Negative meniscus lens L21(fN3 = −92.166)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 2.023 Conditional Expression(16)(−fGa)/f = 0.638 Conditional Expression(17)DN3 = 2.400 <Negative lens L22(fN3 = −93.285)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.016 Conditional Expression(12)νdN3 = 59.30 Conditional Expression(13), (13-1)θgFN3 = 0.5584 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0162 Conditional Expression(15)fN3/fGa = 2.047 Conditional Expression(16)(−fGa)/f = 0.638 Conditional Expression(17)DN3 = 2.000 <Negative lens L24(fN3 = −103.650)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.016 Conditional Expression(12)νdN3 = 59.30 Conditional Expression(13), (13-1)θgFN3 = 0.5584 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0162 Conditional Expression(15)fN3/fGa = 2.274 Conditional Expression(16)(−fGa)/f = 0.638 Conditional Expression(17)DN3 = 2.200

FIG. 10A shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the wide angle end state. FIG. 10B shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the intermediate focal length state. FIG. 10C shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Fifth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Sixth Example

Sixth Example is described with reference to FIGS. 11 and 12A, 12B and 12C and Table 6. FIG. 11 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Sixth Example. The optical system LS(6) according to Sixth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; and a fifth lens group G5 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the second lens group G2 and the fourth lens group G4 move in directions indicated by arrows in FIG. 11. The aperture stop S is disposed in the fifth lens group G5.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a plano-convex positive lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a positive meniscus lens L21 having a convex surface facing the object; a cemented lens consisting of biconvex positive lens L22, and a biconcave negative lens L23; a cemented lens consisting of a biconcave negative lens L24, and a positive meniscus lens L25 having a convex surface facing the object; and a negative meniscus lens L26 having a concave surface facing the object. In this Example, the negative lens L23 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative lens L23 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a biconvex positive lens L32; a biconcave negative lens L33; and a biconvex positive lens L34.

The fourth lens group G4 consists of, in order from the object: a plano-convex positive lens L41 having a convex surface facing the image; and a cemented lens consisting of the biconvex positive lens L42, and a biconcave negative lens L43. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the object along the optical axis.

The fifth lens group G5 consists of, in order from the object: a biconcave negative lens L51; a biconvex positive lens L52; a negative meniscus lens L53 having a convex surface facing the object; a cemented lens consisting of a positive meniscus lens L54 having a concave surface facing the object, and a biconcave negative lens L55; a biconvex positive lens L56; a cemented lens consisting of a negative meniscus lens L57 having a convex surface facing the object, and a biconvex positive lens L58; and a biconcave negative lens L59. An image surface I is disposed on the image side of the fifth lens group G5. An aperture stop S is disposed between the negative lens L51 and the positive lens L52 of the fifth lens group G5. Note that a fixed aperture stop (flare cut stop) Sa is disposed between the negative lens L55 (of the cemented lens) and the positive lens L56.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive lens L13, the positive meniscus lens L21, the cemented lens consisting of the positive lens L22 and the negative lens L23, the cemented lens consisting of the negative lens L24 and the positive meniscus lens L25, the negative meniscus lens L26, the positive lens L31, the positive lens L32, the negative lens L33, the positive lens L34, the positive lens L41, the cemented lens consisting of the positive lens L42 and the negative lens L43, and the negative lens L51 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L52, the negative meniscus lens L53, the cemented lens consisting of the positive meniscus lens L54 and the negative lens L55, the positive lens L56, the cemented lens consisting of the negative meniscus lens L57 and the positive lens L58, and the negative lens L59 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 6 lists values of data on the optical system according to Sixth Example.

TABLE 6 [General Data] Zooming ratio = 2.354 W M T f 123.600 200.000 291.000 FNO 2.910 2.910 2.911 2ω 19.564 12.076 8.292 Y 21.630 21.630 21.630 TL 341.394 341.394 341.394 BF 54.819 54.819 54.819 fF 1986.248 3213.999 4676.377 fR 102.747 102.747 102.747 [Lens Data] Surface Number R D nd νd θgF 1 319.23390 5.200 1.90265 35.77 0.5815 2 151.34780 13.400  1.49782 82.57 0.5386 3 −783.35470 0.100 4 136.11850 13.200  1.43385 95.23 0.5386 5 ∞  D5(Variable) 6 122.06030 7.600 1.72047 34.71 0.5834 7 1981.86560 13.000  8 303.62550 4.700 1.71736 29.57 0.6036 9 −303.62550 2.850 1.65240 55.27 0.5607 10 100.55440 3.315 11 −1987.36830 2.650 1.80400 46.60 0.5575 12 51.73610 3.700 1.66382 27.35 0.6319 13 100.83750 6.065 14 −83.24470 2.500 1.87071 40.73 0.5682 15 −665.86980 D15(Variable) 16 601.42740 4.700 1.75500 52.33 0.5475 17 −159.25800 0.100 18 93.67070 6.800 1.43385 95.23 0.5386 19 −253.82990 1.564 20 −113.21580 5.000 1.65412 39.68 0.5738 21 87.15300 0.975 22 116.35500 5.000 1.91082 35.25 0.5822 23 −377.46590 D23(Variable) 24 ∞ 4.000 1.80400 46.60 0.5575 25 −119.18440 0.100 26 63.25160 6.800 1.59349 67.00 0.5366 27 −196.14820 1.800 1.84666 23.78 0.6192 28 196.14820 D28(Variable) 29 −128.97450 1.900 2.00100 29.13 0.5995 30 94.21930 4.866 31 ∞ 8.000 (Aperture Stop S) 32 416.97790 5.000 1.72916 54.61 0.5443 33 −76.00320 4.000 34 163.99730 2.000 1.80611 40.73 0.5672 35 69.61920 3.496 36 −129.19950 3.600 1.90200 25.26 0.6165 37 −52.57870 1.900 1.62731 59.30 0.5583 38 177.27800 5.206 39 ∞ 9.390 40 78.30600 5.000 2.00100 29.13 0.5995 41 1628.46070 0.100 42 63.86980 3.000 1.80400 46.60 0.5575 43 33.62860 10.000  1.48749 70.32 0.5291 44 −75.31750 6.047 45 −67.14290 2.000 1.90043 37.37 0.5772 46 216.78070 BF [Variable distance data on zoom photographing] W M T D5 5.100 40.193 66.953 D15 63.457 28.364 1.603 D23 21.296 17.639 18.670 D28 6.100 9.757 8.725 [Lens Group Data] Group First surface Focal length G1 1 252.497 G2 6 −70.230 G3 16 107.659 G4 24 91.176 G5 29 −145.483 [Conditional Expression Corresponding Value] <Negative lens L23(fN1 = −115.463)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.013 Conditional Expression(2)νdN1 = 55.27 Conditional Expression(3), (3-1)θgFN1 = 0.5607 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0118 Conditional Expression(5)(−fN1)/fF = 0.058 Conditional Expression(6)(−fN1)/f = 0.934 Conditional Expression(7)DN1 = 2.850 <Negative lens L23(fN3 = −115.463)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.013 Conditional Expression(12)νdN3 = 55.27 Conditional Expression(13), (13-1)θgFN3 = 0.5607 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0118 Conditional Expression(15)fN3/fGa = 1.644 Conditional Expression(16)(−fGa)/f = 0.568 Conditional Expression(17)DN3 = 2.850

FIG. 12A shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the wide angle end state. FIG. 12B shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the intermediate focal length state. FIG. 12C shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Sixth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Seventh Example

Seventh Example is described with reference to FIGS. 13 and 14A, 14B and 14C and Table 7. FIG. 13 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Seventh Example. The optical system LS(7) according to Seventh Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; a fifth lens group G5 having a negative refractive power; and a sixth lens group G6 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to sixth lens groups G1 to G6 move in directions indicated by arrows in FIG. 13. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L11 having a convex surface facing the object; a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object. In this Example, the negative lens L22 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative lens L22 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a negative meniscus lens L32 having a convex surface facing the object, and a biconvex positive lens L33; and a negative meniscus lens L34 having a concave surface facing the object. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The cemented lens consisting of the negative meniscus lens L32 and the positive lens L33 of the third lens group G3 constitutes a vibration-proof lens group (partial group) that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I).

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L41, and a negative meniscus lens L42 having a concave surface facing the object; and a cemented lens consisting of a negative meniscus lens L43 having a convex surface facing the object, and a biconvex positive lens L44. The positive lens L44 has an image-side lens surface that is an aspherical surface.

The fifth lens group G5 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L51, and a biconcave negative lens L52. Upon focusing from the infinity object to the short-distant (finite distant) object, the fifth lens group G5 moves toward the image along the optical axis. The negative lens L52 has an image-side lens surface that is an aspherical surface.

The sixth lens group G6 consists of, in order from the object: a negative meniscus lens L61 having a concave surface facing the object; and a biconvex positive lens L62. An image surface I is disposed on the image side of the sixth lens group G6. The negative meniscus lens L61 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L11, the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the negative meniscus lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the negative meniscus lens L32 and the positive lens L33, the negative meniscus lens L34, the cemented lens consisting of the positive lens L41 and the negative meniscus lens L42, the cemented lens consisting of the negative meniscus lens L43 and the positive lens L44, the cemented lens consisting of the positive lens L51 and the negative lens L52, the negative meniscus lens L61, and the positive lens L62 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 7 lists values of data on the optical system according to Seventh Example.

TABLE 7 [General Data] Zooming ratio = 7.882 W M T f 24.616 105.000 194.013 FNO 4.120 6.306 6.504 2ω 86.537 22.101 12.176 Y 21.039 21.700 21.700 TL 126.886 169.749 190.789 BF 11.756 31.173 39.042 fF −22.178 −43.419 −73.532 fR 26.333 23.348 25.057 [Lens Data] Surface Number R D nd νd θgF  1 198.37380 1.700 1.90366 31.27 0.5948  2 78.64770 0.867  3 81.68370 6.232 1.59319 67.90 0.5440  4 −439.34990 0.100  5 64.30820 5.536 1.59319 67.90 0.5440  6 450.30050  D6(Variable)  7 223.68080 1.100 1.90265 35.72 0.5804  8 19.06430 5.167  9 −52.46300 1.000 1.68348 54.80 0.5501 10 49.37630 0.579 11 34.85960 3.123 1.92286 20.88 0.6390 12 −79.48030 0.778 13 −33.96090 0.902 1.81600 46.59 0.5567 14 −2925.82960 D14(Variable) 15 ∞ 2.000 (Aperture Stop S) 16 42.72150 2.329 1.90265 35.72 0.5804 17 −223.01850 0.500 18 36.53960 1.000 2.00100 29.12 0.5996 19 20.75820 3.544 1.57957 53.74 0.5519 20 −71.54230 1.387 21 −37.29020 1.001 1.95375 32.33 0.5905 22 −437.70110 D22(Variable) 23 37.71780 4.779 1.83481 42.73 0.5648 24 −37.71780 1.000 1.90366 31.27 0.5948 25 −338.61890 0.100 26 31.18000 3.102 1.95375 32.33 0.5905 27 15.34670 8.806 1.49710 81.49 0.5377 28* −42.86350 D28(Variable) 29 490.77490 3.221 1.84666 23.80 0.6215 30 −34.21660 1.001 1.85135 40.13 0.5685 31* 31.39620 D31(Variable) 32 −18.58490 1.400 1.85135 40.13 0.5685 33* −25.93960 0.100 34 179.9029  3.8234 1.68376 37.57 0.5782 35 −92.9069 BF [Aspherical Surface Data] 28th Surface κ = 1.000,A4 = 2.86E−05, A6 = −1.68E−07 A8 = 2.77E−09, A10 = −2.49E−11, A12 = 7.74E−14 31st Surface κ = 1.000, A4 = −7.57279E−06, A6 = 1.58867E−07 A8 = −2.59261E−09, A10 = 2.08033E−11, A12 = −5.7658E−14 33rd Surface κ = 1.000, A4 = −7.21237E−07, A6 = −1.27431E−08 A8 = 8.85331E−11, A10 = −2.09373E−13, A12 = 0.0000E+00 [Variable distance data on zoom photographing] W M T D6 1.562 40.013 56.454 D14 19.428 4.423 1.154 D22 13.086 3.754 1.522 D28 4.931 5.545 1.907 D31 9.947 18.665 24.534 [Lens Group Data] Group First surface Focal length G1 1 103.121 G2 7 −16.904 G3 15 48.856 G4 23 29.282 G5 29 −39.335 G6 32 −6290.822 [Conditional Expression Corresponding Value] <Negative lens L22(fN1 = −37.069)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = −1.671 Conditional Expression(6)(−fN1)/f = 1.506 Conditional Expression(7)DN1 = 1.000 <Negative lens L22(fN3 = −37.069)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 2.193 Conditional Expression(16)(−fGa)/f = 0.687 Conditional Expression(17)DN3 = 1.000

FIG. 14A shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the wide angle end state. FIG. 14B shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the intermediate focal length state. FIG. 14C shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Seventh Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Eighth Example

Eighth Example is described with reference to FIGS. 15 and 16A, 16B and 16C and Table 8. FIG. 15 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Eighth Example. The optical system LS(8) according to Eighth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 15. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; a positive meniscus lens L13 having a convex surface facing the object; and a positive meniscus lens L14 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a biconvex positive lens L23; and a biconcave negative lens L24. In this Example, the negative lens L24 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative lens L24 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a negative meniscus lens L32 having a convex surface facing the object; and a cemented lens consisting of a negative meniscus lens L33 having a convex surface facing the object, and a biconvex positive lens L34. The third lens group G3 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The positive lens L31 has opposite lens surfaces that are aspherical surfaces.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a positive meniscus lens L41 having a concave surface facing the object, and a biconcave negative lens L42. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of, in order from the object: a cemented lens consisting of biconvex positive lens L51, and a negative meniscus lens L52 having a concave surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface. An optical filter FL is disposed between the fifth lens group G5 and the image surface I. The optical filter FL may be, for example, an NC filter (neutral color filter), a color filter, a polarizing filter, an ND filter (neutral density filter), an IR filter (infrared cutoff filter) or the like.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L22, the positive meniscus lens L13, the positive meniscus lens L14, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the negative lens L32, the cemented lens consisting of the negative meniscus lens L33 and the positive lens L34, the cemented lens consisting of the positive meniscus lens L41 and the negative lens L42, and the cemented lens consisting of the positive lens L51 and the negative meniscus lens L52 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 8 lists values of data on the optical system according to Eighth Example.

TABLE 8 [General Data] Zooming ratio = 78.219 W M T f 4.430 13.187 346.510 FNO 2.746 3.489 6.835 2ω 86.498 33.500 1.299 Y 3.350 4.000 4.000 TL 131.989 135.543 198.671 BF 0.400 0.400 0.400 fF −12.191 −16.895 −161.406 fR 24.512 28.996 −59.326 [Lens Data] Surface Number R D nd νd θgF  1 635.18304 2.300 1.78590 44.17 0.5626  2 88.21131 7.500 1.43700 95.10 0.5336  3 −295.14033 0.100  4 87.82570 6.100 1.49782 82.57 0.5386  5 1219.65670 0.100  6 90.98562 4.700 1.49782 82.57 0.5386  7 353.92110  D7(Variable)  8 61.45834 1.000 1.83481 42.73 0.5648  9 11.78636 5.700 10 −21.52038 0.800 1.83481 42.73 0.5648 11 108.15181 0.100 12 28.80632 3.150 1.92286 20.88 0.6390 13 −40.21061 1.090 14 −18.76071 0.700 1.65167 56.24 0.5536 15 322.64495 D15(Variable) 16 ∞ 0.750 (Aperture Stop S) 17* 12.55338 3.000 1.55332 71.68 0.5404 18* −98.92515 2.600 19 23.66805 1.000 1.90366 31.31 0.5947 20 12.27040 1.750 21 16.93839 0.500 1.78590 44.17 0.5626 22 11.18664 3.500 1.49782 82.57 0.5386 23 −27.12612 D23(Variable) 24 −553.37396 2.500 1.53172 48.78 0.5622 25 −25.28953 0.500 1.49782 82.57 0.5386 26 15.03788 D26(Variable) 27* 18.69956 2.100 1.58913 61.22 0.5401 28 −19.90834 0.500 1.71736 29.57 0.6036 29 −53.24372 D29(Variable) 30 ∞ 0.210 1.51680 63.88 0.5360 31 ∞ 0.850 32 ∞ 0.500 1.51680 63.88 0.5360 33 ∞ BF [Aspherical Surface Data] 17th Surface κ = 1.000, A4 = −3.03829E−05, A6 = −3.11384E−07 A8 = 8.41204E−09, A10 = 0.00000E+00, A12 = 0.00000E+00 18th Surface κ = 1.000, A4 = 5.13608E−05, A6 = −3.72416E−07 A8 = 1.42105E−08, A10 = −5.31468E−11, A12 = 0.00000E+00 27th Surface κ = 1.000, A4 = −7.86909E−06, A6 = 2.69411E−07 A8 = −4.51379E−09, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable distance data on zoom photographing] W M T D7 0.750 29.576 96.457 D15 58.597 27.038 1.750 D23 1.000 10.725 20.681 D26 8.328 7.495 24.390 D29 9.314 6.709 1.392 [Lens Group Data] Group First surface Focal length G1 1 121.894 G2 8 −10.354 G3 16 19.925 G4 24 −30.515 G5 27 26.216 [Conditional Expression Corresponding Value] <Negative lens L24(fN1 = −27.185)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.019 Conditional Expression(2)νdN1 = 56.24 Conditional Expression(3), (3-1)θgFN1 = 0.5536 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0063 Conditional Expression(5)(−fN1)/fF = −2.230 Conditional Expression(6)(−fN1)/f = 6.137 Conditional Expression(7)DN1 = 0.700 <Negative lens L24(fN3 = −27.185)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.019 Conditional Expression(12)νdN3 = 56.24 Conditional Expression(13), (13-1)θgFN3 = 0.5536 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0063 Conditional Expression(15)fN3/fGa = 2.626 Conditional Expression(16)(−fGa)/f = 2.337 Conditional Expression(17)DN3 = 0.700

FIG. 16A shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the wide angle end state. FIG. 16B shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the intermediate focal length state. FIG. 16C shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Eighth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Ninth Example

Ninth Example is described with reference to FIGS. 17 and 18A, 18B and 18C and Table 9. FIG. 17 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Ninth Example. The optical system LS(9) according to Ninth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 17. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; a positive meniscus lens L13 having a convex surface facing the object; and a positive meniscus lens L14 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; and a cemented lens consisting of a biconvex positive lens L23, and a biconcave negative lens L24. In this Example, the negative meniscus lens L21 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative meniscus lens L21 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a biconvex positive lens L32, and a biconcave negative lens L33; and a biconvex positive lens L34. The third lens group G3 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The positive lens L31 has opposite lens surfaces that are aspherical surfaces.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L41, and a biconcave negative lens L42.

The fifth lens group G5 consists of, in order from the object: a cemented lens consisting of biconvex positive lens L51, and a negative meniscus lens L52 having a concave surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the fifth lens group G5 moves toward the object along the optical axis. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface. Similar to the Eighth Example, an optical filter FL is disposed between the fifth lens group G5 and the image surface I.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the positive meniscus lens L14, the negative meniscus lens L21, the negative lens L22, the cemented lens consisting of the positive lens L23 and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the positive lens L32 and the negative lens L33, the positive lens L34, the cemented lens consisting of positive lens L41 and the negative lens L42, and the cemented lens consisting of the positive lens L51 and the negative meniscus lens L52 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 9 lists values of data on the optical system according to Ninth Example.

TABLE 9 [General Data] Zooming ratio = 56.908 W M T f 4.397 12.677 250.201 FNO 3.492 4.324 7.259 2ω 87.204 34.976 1.799 Y 3.400 4.000 4.000 TL 102.372 105.195 145.381 BF 0.600 0.600 0.600 fF −10.013 −13.902 −140.788 fR 20.171 20.847 115.149 [Lens Data] Surface Number R D nd νd θgF  1 273.18981 1.800 1.80440 39.61 0.5719  2 65.52782 5.650 1.43700 95.10 0.5336  3 −246.12543 0.200  4 75.42445 3.500 1.49782 82.57 0.5386  5 483.55234 0.200  6 54.82234 4.100 1.49782 82.57 0.5386  7 376.10491  D7(Variable)  8 4953.19040 1.000 1.67769 52.63 0.5546  9 7.50793 4.500 10 −23.16393 0.900 1.83481 42.73 0.5648 11 47.61347 0.200 12 16.11916 3.000 1.92286 20.88 0.6390 13 −143.49864 0.900 1.91082 35.25 0.5822 14 37.59639 D14(Variable) 15 ∞ 0.750 (Aperture Stop S) 16* 12.15820 2.500 1.55332 71.68 0.5404 17* −58.02211 0.200 18 11.49728 2.100 1.49782 82.57 0.5386 19 −77.93882 0.800 1.88300 40.66 0.5668 20 11.77346 0.650 21 137.02945 1.900 1.48749 70.32 0.5291 22 −12.01805 D22(Variable) 23 40.61484 1.200 1.79504 28.69 0.6065 24 −53.39104 0.600 1.79952 42.09 0.5667 25 14.78044 D25(Variable) 26* 7.45330 3.050 1.62299 58.12 0.5438 27 −12.70314 0.800 1.83400 37.18 0.5778 28 −65.93420 D28(Variable) 29 ∞ 0.210 1.51680 63.88 0.5360 30 ∞ 1.348 31 ∞ 0.500 1.51680 63.88 0.5360 32 ∞ BF [Aspherical Surface Data] 16th Surface κ = 1.366, A4 = −3.45996E−05, A6 = 4.67304E−07 A8 = 0.00000E+00,A10 = 0.00000E+00, A12 = 0.00000E+00 17th Surface κ = 1.000, A4 = 1.57317E−04, A6 = 8.62777E−07 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 26th Surface κ = 1.000, A4 = 2.30650E−05, A6 = 1.26895E−07 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable distance data on zoom photographing] W M T D7 0.500 18.937 61.732 D14 42.310 18.734 0.200 D22 1.000 3.984 8.357 D25 9.814 9.840 28.250 D28 5.590 10.542 3.684 [Lens Group Data] Group First surface Focal length G1 1 79.847 G2 8 −8.267 G3 15 15.573 G4 23 −29.814 G5 26 31.361 [Conditional Expression Corresponding Value] <Negative meniscus lens L21(fN1 = −11.061)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.021 Conditional Expression(2)νdN1 = 52.63 Conditional Expression(3), (3-1)θgFN1 = 0.5546 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0012 Conditional Expression(5)(−fN1)/fF = −1.105 Conditional Expression(6)(−fN1)/f = 2.516 Conditional Expression(7)DN1 = 1.000 <Negative meniscus lens L21(fN3 = −11.061)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.021 Conditional Expression(12)νdN3 = 52.63 Conditional Expression(13), (13-1)θgFN3 = 0.5546 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0012 Conditional Expression(15)fN3/fGa = 1.338 Conditional Expression(16)(−fGa)/f = 1.880 Conditional Expression(17)DN3 = 1.000

FIG. 18A shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the wide angle end state. FIG. 18B shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the intermediate focal length state. FIG. 18C shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Ninth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Tenth Example

Tenth Example is described with reference to FIGS. 19 and 20A, 20B and 20C and Table 10. FIG. 19 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Tenth Example. The optical system LS(10) according to Tenth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fourth lens groups G1 to G4 move in directions indicated by arrows in FIG. 19. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object. In this Example, the negative meniscus lens L21 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative meniscus lens L21 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a positive meniscus lens L32 having a convex surface facing the object, and a negative meniscus lens L33 having a convex surface facing the object; and a biconvex positive lens L34. The third lens group G3 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The positive lens L31 has opposite lens surfaces that are aspherical surfaces.

The fourth lens group G4 consists of a negative meniscus lens L41 having a convex surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of a biconvex positive lens L51. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface. Similar to the Eighth Example, an optical filter FL is disposed between the fifth lens group G5 and the image surface I.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the negative meniscus lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the positive meniscus lens L32 and the negative meniscus lens L33, the positive lens L34, the negative meniscus lens L41, and the positive lens L51 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 10 lists values of data on the optical system according to Tenth Example.

TABLE 10 [General Data] Zooming ratio = 32.853 W M T f 4.432 10.612 145.611 FNO 3.567 4.361 7.435 2ω 85.001 40.168 3.043 Y 3.300 4.000 4.000 TL 68.023 68.790 99.945 BF 0.400 0.400 0.400 fF −7.660 −9.862 −59.394 fR 21.418 26.678 −30.263 [Lens Data] Surface Number R D nd νd θgF  1 102.43988 0.950 1.80100 34.92 0.5853  2 36.00812 3.750 1.49700 81.73 0.5371  3 −149.20420 0.100  4 34.83218 2.650 1.60300 65.44 0.5389  5 280.45373  D5(Variable)  6 60.18046 0.500 1.62731 59.30 0.5584  7 6.30550 3.715  8 −12.51258 0.550 1.90366 31.31 0.5947  9 30.14088 0.100 10 15.65323 2.400 1.92286 20.88 0.639 11 −15.92321 0.400 12 −10.47990 0.550 1.80610 40.97 0.5688 13 −89.27818 D13(Variable) 14 ∞ 0.700 (Aperture Stop S) 15* 7.22087 2.200 1.49710 81.56 0.5385 16* −25.69859 0.100 17 9.11323 2.200 1.53172 48.78 0.5622 18 75.26227 0.400 1.91082 35.25 0.5822 19 6.37325 0.650 20 14.90902 1.700 1.49700 81.73 0.5371 21 −16.93987 D21(Variable) 22 18.44495 0.600 1.49700 81.73 0.5371 23 6.77356 D23(Variable) 24* 11.50000 2.200 1.53113 55.75 0.5628 25 −35.52133 0.600 26 ∞ 0.210 1.51680 63.88 0.5360 27 ∞ 0.450 28 ∞ 0.500 1.51680 63.88 0.5360 29 ∞ BF [Aspherical Surface Data] 15th Surface κ = −1.173, A4 = 4.61200E−04, A6 = −1.72721E−06 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 16th Surface κ = 1.000, A4 = 1.73828E−04, A6 = 8.92317E−07 A8 = −5.35697E−08, A10 = 0.00000E+00, A12 = 0.00000E+00 24th Surface κ = 2.877, A4 = −1.20577E−04, A6 = 2.62458E−06 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable distance data on zoom photographing] W M T D5 0.278 10.454 39.970 D13 26.913 13.530 1.598 D21 2.982 8.797 15.299 D23 9.275 7.435 14.504 [Lens Group Data] Group First surface Focal length G1 1 55.798 G2 6 −6.256 G3 14 11.856 G4 22 −21.912 G5 24 16.626 [Conditional Expression Corresponding Value] <Negative meniscus lens L21(fN1 = −11.268)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.016 Conditional Expression(2)νdN1 = 59.30 Conditional Expression(3), (3-1)θgFN1 = 0.5584 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0162 Conditional Expression(5)(−fN1)/fF = −1.471 Conditional Expression(6)(−fN1)/f = 2.542 Conditional Expression(7)DN1 = 0.500 <Negative meniscus lens L21(fN3 = −11.268)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.016 Conditional Expression(12)νdN3 = 59.30 Conditional Expression(13), (13-1)θgFN3 = 0.5584 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0162 Conditional Expression(15)fN3/fGa = 1.801 Conditional Expression(16)(−fGa)/f = 1.411 Conditional Expression(17)DN3 = 0.500

FIG. 20A shows various aberration graphs of the optical system according to Tenth Example upon focusing on infinity in the wide angle end state. FIG. 20B shows various aberration graphs of the optical system according to Tenth Example upon focusing on infinity in the intermediate focal length state. FIG. 20C shows various aberration graphs of the optical system according to Tenth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Tenth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Eleventh Example

Eleventh Example is described with reference to FIGS. 21 and 22A, 22B and 22C and Table 11. FIG. 21 is a diagram showing a lens configuration of an optical system (zoom optical system) in a state upon focusing on infinity according to Eleventh Example. The optical system LS(11) according to Eleventh Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 21. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; a positive meniscus lens L13 having a convex surface facing the object; and a positive meniscus lens L14 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a biconvex positive lens L23; and a cemented lens consisting of a biconcave negative lens L24, and a positive meniscus lens L25 having a convex surface facing the object. In this Example, the negative lens L24 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (1) to (4) and the like. In this Example, the second lens group G2 corresponds to an object-side negative lens group, and the negative lens L24 of the second lens group G2 corresponds to a negative lens that satisfies the conditional expressions (11) to (14) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a negative meniscus lens L32 having a convex surface facing the object; and a cemented lens consisting of a negative meniscus lens L33 having a convex surface facing the object, and a biconvex positive lens L34. The third lens group G3 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The positive lens L31 has opposite lens surfaces that are aspherical surfaces.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L41, and a biconcave negative lens L42. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of, in order from the object: a cemented lens consisting of biconvex positive lens L51, and a negative meniscus lens L52 having a concave surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface. Similar to the Eighth Example, an optical filter FL is disposed between the fifth lens group G5 and the image surface I.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the positive meniscus lens L14, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the cemented lens consisting of the negative lens L24 and the positive meniscus lens L25 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the negative meniscus lens L32, the cemented lens consisting of the negative meniscus lens L33 and the positive lens L34, the cemented lens consisting of the positive lens L41 and the negative lens L42, and the cemented lens consisting of the positive lens L51 and the negative meniscus lens L52 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 11 lists values of data on the optical system according to Eleventh Example. Note that the sixth surface, and the nineteenth surface are virtual surfaces.

TABLE 11 [General Data] Zooming ratio = 118.076 W M T f 4.429 14.376 523.001 FNO 2.820 3.650 8.128 2ω 85.436 30.806 0.863 Y 3.350 4.000 4.000 TL 167.110 170.132 264.500 BF 0.540 0.540 0.540 fF −12.897 −17.631 −239.375 fR 32.087 42.873 −80.219 [Lens Data] Surface Number R D nd νd OgF  1 825.93933 2.900 1.80400 46.60 0.5575  2 112.39133 7.800 1.43700 95.10 0.5336  3 −453.66816 0.100  4 115.49170 6.300 1.49782 82.57 0.5386  5 9088.66420 0.100  6 ∞ 0.000  7 133.81125 4.700 1.49782 82.57 0.5386  8 571.60343  D8(Variable)  9 55.85227 1.300 1.87071 40.73 0.5682 10 13.94864 7.000 11 −32.19593 1.200 1.80420 46.50 0.5572 12 57.84873 0.100 13 28.64191 3.800 1.90200 25.26 0.6165 14 −70.26333 1.600 15 −20.59922 1.000 1.68348 54.80 0.5501 16 39.38825 1.800 1.92286 20.88 0.6390 17 139.67089 D17(Variable) 18 ∞ 0.600 (Aperture Stop S) 19 ∞ 1.106 20* 13.03513 4.100 1.49710 81.56 0.5385 21* −80.65458 2.800 22 26.48603 1.200 1.91082 35.25 0.5822 23 11.88277 2.000 24 14.86421 1.200 1.77250 49.62 0.5518 25 11.87360 3.600 1.49782 82.57 0.5386 26 −35.53498 D26(Variable) 27 509.89664 1.200 1.53172 48.78 0.5622 28 −22.32829 0.700 1.49700 81.61 0.5389 29 17.44965 D29(Variable) 30* 18.42875 2.000 1.58913 61.22 0.5401 31 −31.60931 0.600 1.75520 27.57 0.6092 32 −241.53196 D32(Variable) 33 ∞ 0.400 1.51680 63.88 0.5360 34 ∞ 0.700 35 ∞ 0.500 1.51680 63.88 0.5360 36 ∞ BF [Aspherical Surface Data] 20th Surface κ = 1.000, A4 = −3.21091E−05, A6 = −8.68271E−08 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 21st Surface κ = 1.000, A4 = 3.10451E−05, A6 = −2.93413E−08 A8 = 7.59720E−10, A10 = 0.00000E+00, A12 = 0.00000E+00 30th Surface κ = 1.000, A4 = −1.73347E−06, A6 = 0.00000E+00 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable distance data on zoom photographing] W M T D8 0.750 41.177 143.201 D17 80.493 34.159 1.024 D26 2.275 10.638 22.193 D29 14.580 16.417 33.124 D32 6.065 4.795 2.012 [Lens Group Data] Group First surface Focal length G1 1 170.892 G2 9 −11.362 G3 18 22.993 G4 27 −38.719 G5 30 33.447 [Conditional Expression Corresponding Value] <Negative lens L24(fN1 = −19.656)> Conditional Expression(1) ndN1 − (2.015 − 0.0068 × νdN1) = 0.041 Conditional Expression(2)νdN1 = 54.80 Conditional Expression(3), (3-1)θgFN1 = 0.5501 Conditional Expression(4), (4-1) θgFN1 − (0.6418 − 0.00168 × νdN1) = 0.0004 Conditional Expression(5)(−fN1)/fF = −1.524 Conditional Expression(6)(−fN1)/f = 4.438 Conditional Expression(7)DN1 = 1.000 <Negative lens L24(fN3 = −19.656)> Conditional Expression(11) ndN3 − (2.015 − 0.0068 × νdN3) = 0.041 Conditional Expression(12)νdN3 = 54.80 Conditional Expression(13), (13-1)θgFN3 = 0.5501 Conditional Expression(14), (14-1) θgFN1 − (0.6418 − 0.00168 × νdN3) = 0.0004 Conditional Expression(15)fN3/fGa = 1.730 Conditional Expression(16)(−fGa)/f = 2.565 Conditional Expression(17)DN3 = 1.000

FIG. 22A shows various aberration graphs of the optical system according to Eleventh Example upon focusing on infinity in the wide angle end state. FIG. 22B shows various aberration graphs of the optical system according to Eleventh Example upon focusing on infinity in the intermediate focal length state. FIG. 22C shows various aberration graphs of the optical system according to Eleventh Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Eleventh Example has favorably corrected various aberrations, and exerts excellent imaging performance.

According to each Example, the optical system or the zoom optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected can be achieved.

Here, Examples described above show specific examples of the invention of the present application. The invention of the present application is not limited to these Examples.

Note that the following content can be adopted in a range without impairing the optical performance of the optical system of this embodiment.

The focusing lens group is assumed to indicate a portion that includes at least one lens separated by air distances changing upon focusing. That is, a focusing lens group may be adopted that moves a single or multiple lens groups, or a partial lens group in the optical axis direction to achieve focusing from the infinity object to the short-distant object. The focusing lens group is also applicable to autofocusing, and is suitable also for motor drive for autofocusing (using an ultrasonic motor).

In Second, Fifth, and Seventh to Eleventh Examples, the configurations having the vibration-proof function are described. However, the present application is not limited thereto, and may adopt a configuration having no vibration-proof function. The other Examples having no vibration-proof function may have a configuration having the vibration-proof function.

The lens surface may be made of a spherical surface or a planar surface, or an aspherical surface. A case where the lens surface is a spherical surface or a planar surface is preferable because lens processing, and assembling and adjustment are facilitated, and the optical performance degradation due to errors caused by processing and assembling and adjustment can be prevented. Furthermore, it is preferable because the degradation in representation performance even with the image surface being misaligned is small.

In a case where the lens surface is an aspherical surface, the aspherical surface may be any of an aspherical surface made by a grinding process, a glass mold aspherical surface made by forming glass into an aspherical shape with a mold, and a composite type aspherical surface made by forming a resin on a surface of glass into an aspherical shape. The lens surface may be a diffractive surface. The lens may be a gradient-index lens (GRIN lens), or a plastic lens.

An antireflection film having a high transmissivity in a wide wavelength region may be applied onto each lens surface in order to reduce flares and ghosts and achieve optical performances having a high contrast. Accordingly, flares and ghosts can be reduced, and high optical performances having a high contrast can be achieved.

EXPLANATION OF NUMERALS AND CHARACTERS G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group I Image surface S Aperture stop 

1. An optical system, comprising: an aperture stop; and a negative lens that is disposed closer to an object than the aperture stop, wherein the negative lens satisfies the following conditional expressions: −0.010<ndN1−(2.015−0.0068×νdN1), 50.00<νdN1<65.00, 0.545<θgFN1, −0.010<θgFN1−(0.6418−0.00168×νdN1), where ndN1: a refractive index of the negative lens for d-line, νdN1: an Abbe number of the negative lens with reference to d-line, and θgFN1: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN1, a refractive index of the negative lens for F-line is nFN1, and a refractive index of the negative lens for C-line is nCN1: θgFN1=(ngN1−nFN1)/(nFN1−nCN1).
 2. The optical system according to claim 1, consisting of: the aperture stop; a front group disposed closer to the object than the aperture stop; and a rear group disposed closer to an image than the aperture stop, wherein the front group includes the negative lens and satisfies the following conditional expression: −10.00<(−fN1)/fF<10.00, where fN1: a focal length of the negative lens, and fF: a focal length of the front group; in a case where the optical system is a zoom optical system, the focal length of the front group in wide angle end state.
 3. The optical system according to claim 1, wherein the negative lens satisfies the following conditional expression: 0.10<(−fN1)/f<15.00, where fN1: the focal length of the negative lens, and f: a focal length of the optical system; in a case where the optical system is a zoom optical system, the focal length of the optical system in wide angle end state.
 4. The optical system according to claim 1, wherein the negative lens satisfies the following conditional expression: 0.555<θgFN1.
 5. The optical system according to claim 1, wherein the negative lens satisfies the following conditional expression: 0.010<θgFN1−(0.6418−0.00168×νdN1).
 6. The optical system according to claim 1, wherein the negative lens satisfies the following conditional expression: DN1>0.400 [mm] where DN1: a thickness of the negative lens on an optical axis.
 7. The optical system according to claim 1, wherein the negative lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other.
 8. The optical system according to claim 1, wherein at least one lens surface of an object-side lens surface and an image-side lens surface of the negative lens is in contact with air.
 9. The optical system according to claim 1, wherein the negative lens is a glass lens.
 10. An optical apparatus comprising the optical system according to claim
 1. 11. A method for manufacturing an optical system, the method comprises a step of arranging, in a lens barrel, an aperture stop and a negative lens that is disposed closer to an object than the aperture stop, the negative lens satisfying the following conditional expressions: −0.010<ndN1−(2.015−0.0068×νdN1), 50.00<νdN1<65.00, 0.545<θgFN1, −0.010<θgFN1−(0.6418−0.00168×νdN1), where ndN1: a refractive index of the negative lens for d-line, νdN1: an Abbe number of the negative lens with reference to d-line, and θgFN1: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN1, a refractive index of the negative lens for F-line is nFN1, and a refractive index of the negative lens for C-line is nCN1: θgFN1=(ngN1−nFN1)/(nFN1−nCN1).
 12. A zoom optical system, comprising a plurality of lens groups that include lens groups having negative refractive powers, wherein upon zooming, a distance between the lens groups adjacent to each other changes, and an object-side negative lens group disposed closest to an object among the lens groups having the negative refractive powers includes a negative lens that satisfies the following conditional expressions: −0.010<ndN3−(2.015−0.0068×νdN3), 50.00<νdN3<65.00, 0.545<θgFN3, −0.010<θgFN3−(0.6418−0.00168×νdN3), where ndN3: a refractive index of the negative lens for d-line, νdN3: an Abbe number of the negative lens with reference to d-line, and θgFN3: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN3, a refractive index of the negative lens for F-line is nFN3, and a refractive index of the negative lens for C-line is nCN3: θgFN3=(ngN3−nFN3)/(nFN3−nCN3).
 13. The zoom optical system according to claim 12, wherein the negative lens satisfies the following conditional expression: 0.50<fN3/fGa<7.00 where fN3: the focal length of the negative lens, and fGa: a focal length of the object-side negative lens group.
 14. The zoom optical system according to claim 12, wherein the object-side negative lens group satisfies the following conditional expression: 0.20<(−fGa)/f<3.50 where fGa: a focal length of the object-side negative lens group, and f: a focal length of the zoom optical system in a wide angle end state.
 15. The zoom optical system according to claim 12, wherein the negative lens satisfies the following conditional expression: 0.555<θgFN3.
 16. The zoom optical system according to claim 12, wherein the negative lens satisfies the following conditional expression: 0.010<θgFN3−(0.6418−0.00168×νdN3).
 17. The zoom optical system according to claim 12, wherein the negative lens satisfies the following conditional expression: DN3>0.400 [mm] where DN3: a thickness of the negative lens on an optical axis.
 18. The zoom optical system according to claim 12, wherein the negative lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other.
 19. The zoom optical system according to claim 12, wherein at least one lens surface of an object-side lens surface and an image-side lens surface of the negative lens is in contact with air.
 20. The zoom optical system according to claim 12, wherein the negative lens is a glass lens.
 21. An optical apparatus comprising the zoom optical system according to claim
 12. 22. A method for manufacturing a zoom optical system that includes a plurality of lens groups including lens groups having negative refractive powers, the method comprises a step of arranging the plurality of lens groups in a lens barrel so that upon zooming, a distance between the lens groups adjacent to each other changes, and an object-side negative lens group disposed closest to an object among the lens groups having the negative refractive powers includes a negative lens that satisfies the following conditional expressions: −0.010<ndN3−(2.015−0.0068×νdN3), 50.00<νdN3<65.00, 0.545<θgFN3, −0.010<θgFN3−(0.6418−0.00168×νdN3), where ndN3: a refractive index of the negative lens for d-line, νdN3: an Abbe number of the negative lens with reference to d-line, and θgFN3: a partial dispersion ratio of the negative lens, defined by a following expression when a refractive index of the negative lens for g-line is ngN3, a refractive index of the negative lens for F-line is nFN3, and a refractive index of the negative lens for C-line is nCN3: θgFN3=(ngN3−nFN3)/(nFN3−nCN3). 